Description from Flora of China
Annuals 5-12 cm tall. Roots stout, fibrous. Stems ascending to erect, subquadrangular, narrowly winged on angles, dichotomously branched from base. Basal leaves with petiole 0.8-2 cm; leaf blade spatulate, 0.7-1.5 cm × 5-9 mm, base obtuse, apex rounded, veins 3-5. Stem leaves sessile or short petiolate; leaf blade ovate-lanceolate, 0.6-2.2 cm × 3-12 mm, base rounded to truncate, apex acute, veins 1-3. Flowers in forks of stems, 4merous. Pedicel slender, somewhat nodding, 0.7-3 cm, 4angled, narrowly winged on angles. Calyx lobes broadly ovate, 3-4 mm, margin scabrous, apex acute; veins 1-3, indistinct. Corolla white, sometimes with or without purple spots, tube ca. 0.5 mm; lobes ovate, 5-8 mm, apex obtuse. Nectaries 2 per corolla lobe, brown, orbicular, squamose, produced into a very short spur on back of corolla lobe. Filaments ca. 2 mm, base short fimbriate; anthers blue, ellipsoid, ca. 0.5 mm. Style short, distinct; stigma lobes capitate. Capsules ovoid-ellipsoid. Seeds yellow, ellipsoid; seed coat smooth. Fl. and fr. May-Jul.
1000-3100 m. Gansu, Hebei, Heilongjiang, Hubei, Jilin, Liaoning, Nei Mongol, Ningxia, Qinghai, Shaanxi, Shandong, Shanxi, N Sichuan, Xinjiang [Japan, Kazakhstan, Mongolia, Russia (Siberia)]